Semiquantitative grading of severity of mitral regurgitation by real-time two-dimensional Doppler flow imaging technique

An attempt was made to determine whether mitral regurgitation could be detected and its severity evaluated semiquantitatively by newly developed real-time two-dimensional Doppler flow imaging in 109 patients who underwent left ventriculography. In the Doppler flow imaging technique, Doppler signals due to blood flow in the cardiac chambers are processed using a high speed autocorrelation technique, so that the direction, velocity and turbulence of the intracardiac blood flow are displayed in the color-coded mode on the monochrome B-mode echocardiogram in real time. Mitral regurgitant flow was imaged as a jet spurting out from the mitral valve orifice into the left atrial cavity. It was noted that the regurgitant jet in the left atrial cavity had a variety of orientations and dynamic features when studied by the present technique. The sensitivity of the technique in the detection of mitral regurgitation was 86% as compared with that of left ventriculography. Mitral regurgitation in the false negative cases was mostly mild. On the basis of the farthest distance reached by the regurgitant flow signal from the mitral valve orifice, the severity of regurgitation was graded on a four point scale and these results were compared with those of angiography. A significant correlation (r = 0.87) was found between Doppler imaging and angiography in the evaluation of the severity of mitral regurgitation. A similar result was obtained for the evaluation based on the area covered by the regurgitant signals in the left atrial cavity. Thus, noninvasive semiquantitative evaluation by real-time two-dimensional Doppler flow imaging appears to be a promising clinical technique.     

Limitations of qualitative angiographic grading in aortic or mitral regurgitation

This study was performed to assess the accuracy of qualitative angiographic grading in persons with aortic regurgitation (AR) or mitral regurgitation (MR) and to determine the factors that may influence the reliability of such grading. In 230 patients (152 men, 78 women, aged 52 ± 14 years) with AR or MR, forward cardiac index was measured by the Fick and indicator dilution techniques and left ventricular (LV) angiographic index by the area-length method, from which the regurgitant volume index was calculated. In 124 other patients (89 men, 35 women, aged 52 ± 11 years) without regurgitation, there was good agreement between forward and angiographic cardiac indexes (r = 0.87, p < 0.001). In the 83 patients with AR, the regurgitant volume indexes in those with 1+ (0.87 ± 0.57 liters/min/m²) and 2+ (1.72 ± 1.19 liters/min/m²) angiographic regurgitation were not significantly different from one another, but were significantly different from those with 3+ (3.0 ± 1.42 liters/min/m²) and 4+ (4.80 ± 2.25 liters/min/m²⁺) regurgitation; at the same time, the regurgitant volume indexes of patients with 3+ and 4+ AR were not significantly different from one another. In the 147 patients with MR, the regurgitant volume indexes in patients with 1+ regurgitation (0.61 ± 0.64 liters/min/m²) were significantly lower than other grades, but the regurgitant volume indexes of 2+ (1.14 ± 0.85 liters/min/m²⁺) vs 3+ (2.14 ± 1.37 liters/min/m²) and of 3+ vs 4+ (4.60 ± 2.31 liters/min/m²⁺) were not significantly different. With AR and MR, regurgitant flow within each angiographic grade varied widely, especially in grades 3+ and 4+, and there was considerable overlap of regurgitant volume indexes between grades. In patients with an LV end-diastolic volume index ≥ 120 ml/m², the angiographic grading of regurgitation was particularly likely to underestimate the regurgitant volume index. At the same time, the reliability of angiographic grading was not influenced by an enlarged LV end-systolic volume index, a depressed LV ejection fraction, a low forward cardiac index, or an elevated LV end-diastolic or pulmonary capillary wedge pressure. Thus, in patients with AR or MR, the angiographic grading of regurgitation often is at variance with the measured regurgitant volume index, especially in patients with enlarged left ventricles.     

Semiquantitative grading of mitral regurgitation by color-coded Doppler echocardiography

We evaluated patients with mitral regurgitation by color-coded Doppler echocardiography using a semiquantitative score system, which is useful in the clinical setting, by providing rapid discrimination between mild, moderate and severe regurgitation. The study was performed in 42 patients (19 female, 23 male) mean age 58 years, range 23-75 years with mitral regurgitation of different etiology. Color-coded Doppler measurements were compared to angiographic findings using a three point score system. In addition to such parameters as maximal jet length, area and the ratio jet area/left atrial area, we also considered the duration of regurgitant flow. The best correlation was obtained for the maximal area of the jet multiplied by the duration of regurgitant flow/cycle length (r = 0.88), determined in the apical plane where the jet was best visualized. For the parameter area of jet alone, the correlation coefficient was 0.81, for the length of the jet the value was r = 0.65 and comparison of the areas of jet and left atrium gave a coefficient of 0.77. A clear separation between mild and severe regurgitation was observed only for the parameter calculated by multiplying the area of the jet by the duration of mitral regurgitation. In only 7% of the patients with moderate and severe regurgitation could we observe an overlap. This parameter, therefore, represents a useful method for estimating in a semiquantitative manner the severity of mitral regurgitation by color-coded Doppler echocardiography.     

Frequency and severity of mitral regurgitation one year after balloon mitral valvuloplasty

Mitral regurgitation (MR) was evaluated by Doppler echocardiography in 59 patients with mitral stenosis before, immediately after and 1 year after balloon mitral valvuloplasty (BMV). The severity of MR was graded on a scale from 1+ to 4+. Echocardiographic and hemodynamic variables were analyzed to study the potential factor(s) that might predict the long-term persistence of MR. Echocardiographic variables were mitral valve thickness and motion, subvalvular change, left atrial dimension, commissural calcification and effective balloon/mitral anular diameters. Hemodynamic variables were mitral pressure gradient, pulmonary arterial pressure, ejection fraction, mitral valve area index, age, gender and cardiac rhythm. Mitral valve area index increased from 0.9 +/- 0.5 to 1.5 +/- 0.8 cm2/m2 immediately after BMW, and to 1.4 +/- 0.3 cm2/m2 at 1 year follow-up (p less than 0.01). Immediately after BMV, MR grading did not change in 30 patients (51%), increased by 1+ in 23 patients (39%), by 2+ in 2 patients (3.3%) and by 3+ in 2 patients (3.3%), and decreased by 1+ in 2 others. At 1-year follow-up, only 1 patient with severe MR required valve replacement. Fifty-one patients (88%) had no change in the extent of MR (less than or equal to 1+) and 6 patients (10%) had a 1-grade decrease in their MR; only 1 patient had a 1-grade increase in MR. No clinical or hemodynamic variables or morphologic characteristics of the mitral valve could predict the development of significant MR after BMV. It is concluded that an increment in MR severity less than or equal to 2+ is frequently seen after BMV.(ABSTRACT TRUNCATED AT 250 WORDS)     

Unusual cases of acute mitral valve regurgitation

Severe acute mitral regurgitation without early surgical correction can lead to congestive left-sided heart failure and quick death. Traumatic mechanism is one of its rare causes and is described in the literature mainly after blunt chest injuries in car accidents. In our case reports, we deal with cases of patients who have been diagnosed with a significant mitral regurgitation with rupture of chordae tendineae with symptoms of left ventricular failure requiring cardiac surgery. The onset of symptoms was associated with traumatic events of small or mild intensity.     

Underestimation of severity of mitral regurgitation with varying hemodynamics.

Transesophageal echocardiography (TEE) is a valuable technique to assess mitral valve anatomy and the mechanism of mitral regurgitation (MR). We present the case of a 35-year-old woman with severe MR due to restrictive motion of the posterior mitral leaflet, who was referred for mitral annuloplasty. Under physiologic circumstances, a severe (grade 3+) MR was present, whereas in the operating room during general anesthesia, the MR had disappeared almost completely. The downgrading of MR due to general anesthesia and the associated mechanisms of this phenomenon are discussed in this case.     

瓣中瓣置入术治疗二尖瓣关闭不全16例报告

二尖瓣关闭不全患者行常规二尖瓣置换术后常有左室功能恶化，有人推测术中二尖瓣结构的破坏是导致术后左室功能不全的主要机制之一。从１９９１年５月～１９９５年５月，我们对１６例二尖瓣关闭不全患者实施了一种新的二尖瓣置换术，即“瓣中瓣”置入术。术中保留全部二尖瓣瓣叶及瓣下结构，人工瓣置入固定后，前、后瓣叶均卷缩折叠于缝合环下。术后所有患者病情平稳，仅３例需要很少量的正性肌力药物支持，且都能在术后３６小时内脱离呼吸机。经超声心动图测定，术后左室功能很快恢复，所有患者均痊愈出院。结果表明：对二尖瓣关闭不全及其合并轻度狭窄者采用瓣中瓣置入术，有利于术后左室功能的恢复，瓣中瓣置入术是一种安全和有效的手术方法。     

Comparison of echocardiographic methods in assessing severity of mitral regurgitation in patients with mitral valve prolapse

BACKGROUND AND AIM OF THE STUDY: Mitral regurgitation (MR) shows different characteristics in mitral valve prolapse (MVP); hence, it is important to assess MR severity accurately in these patients. The study aim was to compare Doppler echocardiographic methods in making such assessment. METHODS: Forty-seven patients with confirmed MVP and at least moderate mitral insufficiency, as established by Doppler echocardiography, were studied. Quantitative Doppler was used as the reference standard method. Color Doppler mapping was used to determine regurgitant jet area (JA/LAA), flow convergence (EROA-PISA) and vena contracta width (VCW). Systolic pulmonary venous flow reversal (SPVFR) and mitral E-wave velocity were also monitored. RESULTS: Univariate analysis showed severe MR to be significantly correlated to age, presence of atrial fibrillation, left ventricular systolic and diastolic diameter, left atrial diameter, mitral E velocity, JA/LAA, VCW, EROA-PISA and the presence of SPVFR. On multivariate analysis, the strongest determinants of severe MR were EROA-PISA, VCW and E velocity. The greatest area under the receiver-operator curve for diagnosing severe MR was observed with EROA-PISA. The 45-mm2 threshold of EROA-PISA had the highest risk ratio of severe MR with a high sum of sensitivity and specificity. However, the JA/LAA had the lowest risk ratio and negative predictive value for severe MR. CONCLUSION: PISA, VCW, E velocity and SPVFR measurements may be used to evaluate MR severity semi-quantitatively in patients with MVP; however, the ratio of JA/LAA appears to be a less reliable method in this respect.     

Chordal force distribution determines systolic mitral leaflet configuration and severity of functional mitral regurgitation

OBJECTIVES: The purpose of this study was to investigate the impact of the chordae tendineae force distribution on systolic mitral leaflet geometry and mitral valve competence in vitro. BACKGROUND: Functional mitral regurgitation is caused by changes in several elements of the valve apparatus. Interaction among these have to comply with the chordal force distribution defined by the chordal coapting forces (F(c)) created by the transmitral pressure difference, which close the leaflets and the chordal tethering forces (FT) pulling the leaflets apart. METHODS: Porcine mitral valves (n = 5) were mounted in a left ventricular model where leading edge chordal forces measured by dedicated miniature force transducers were controlled by changing left ventricular pressure and papillary muscle position. Chordae geometry and occlusional leaflet area (OLA) needed to cover the leaflet orifice for a given leaflet configuration were determined by two-dimensional echo and reconstructed three-dimensionally. Occlusional leaflet area was used as expression for incomplete leaflet coaptation. Regurgitant fraction (RF) was measured with an electromagnetic flowmeter. RESULTS: Mixed procedure statistics revealed a linear correlation between the sum of the chordal net forces, sigma[Fc - FT]S, and OLA with regression coefficient (minimum - maximum) beta = -115 to -65 [mm2/N]; p < 0.001 and RF (beta = -0.06 to -0.01 [%/N]; p < 0.001). Increasing FT by papillary muscle malalignment restricted leaflet mobility, resulting in a tented leaflet configuration due to an apical and posterior shift of the coaptation line. Anterior leaflet coapting forces increased due to mitral leaflet remodeling, which generated a nonuniform regurgitant orifice area. CONCLUSIONS: Altered chordal force distribution caused functional mitral regurgitation based on tented leaflet configuration as observed clinically.     

The mitral regurgitation index: an echocardiographic guide to severity

OBJECTIVES

The purpose of this study was to develop a semiquantitative index of mitral regurgitation severity suitable for use in daily clinical practice and research.

BACKGROUND

There is no simple method for quantification of mitral regurgitation (MR). The MR Index is a semiquantitative guide to MR severity. The MR Index is a composite of six echocardiographic variables: color Doppler regurgitant jet penetration and proximal isovelocity surface area, continuous wave Doppler characteristics of the regurgitant jet and tricuspid regurgitant jet-derived pulmonary artery pressure, pulse wave Doppler pulmonary venous flow pattern and two-dimensional echocardiographic estimation of left atrial size.

METHODS

Consecutive patients (n = 103) with varying grades of MR, seen in the Adult Echocardiography Laboratory at UCSF, were analyzed retrospectively. All patients were evaluated for the six variables, each variable being scored on a four point scale from 0 to 3. The reference standards for MR were qualitative echocardiographic evaluation by an expert and quantitation of regurgitant fraction using two-dimensional and Doppler echocardiography. A subgroup of patients with low ejection fraction (EF <50%) were also analyzed.

RESULTS

The MR Index increased in proportion to MR severity with a significant difference among the three grades in both normal and low EF groups (F = 130 and F = 42, respectively, p < 0.0001). The MR Index correlated with regurgitant fraction (r = 0.76, p < 0.0001). An MR Index ≥2.2 identified 26/29 patients with severe MR (sensitivity = 90%, specificity = 88%, PPV = 79%). No patient with severe MR had an MR Index <1.8 and no patient with mild MR had an MR Index >1.7.

CONCLUSIONS

The MR Index is a simple semiquantitative estimate of MR severity, which seems to be useful in evaluating MR in patients with a low EF.     

Continuous wave Doppler echocardiographic evaluations of the severity of mitral regurgitation

To ascertain the usefulness of continuous wave Doppler echocardiography in evaluating the severity of mitral regurgitation (MR), 29 patients with MR and 10 normal subjects were examined. The patients were categorized in three groups according to the angiographic evidence of severity of MR. To analyze the flow velocity patterns of MR, the time to peak velocity index (time from onset of MR signal to peak flow velocity/duration of MR signal), the A/B ratio (the ratio of the first and second half of the systolic MR signal area), systolic peak velocity, and diastolic peak velocity were measured using continuous wave Doppler echocardiograms. The velocity patterns of MR differed significantly among the three groups. With severer MR, the flow velocity pattern showed an earlier appearance of the peak in systole, a steeper decrease in systole and a greater increase in early diastole. The time to peak velocity index was 55 +/- 7% (mean +/- SD) in mild MR, 42 +/- 6% in moderate MR and 35 +/- 5% in severe MR. This index shortened significantly in accord with the severity of MR (mild vs moderate MR: p less than 0.001, moderate vs severe MR: p less than 0.05). The A/B ratio was 1.06 +/- 0.12 in mild MR, 1.23 +/- 0.10 in moderate MR and 1.41 +/- 0.07 in severe MR. This ratio increased significantly with the severity of MR (mild vs moderate MR: p less than 0.01, moderate vs severe MR: p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Moderate exercise does not increase the severity of mitral regurgitation due to mitral valve prolapse

Background: Mitral regurgitation (MR) secondary to ischemic heart disease (IHD) increases during exercise. We tested the hypothesis that the same is also true for MR due to mitral valve prolapse (MVP). Methods: Consecutive patients with asymptomatic MR of varying severity underwent exercise test on a supine bicycle with workload up to a maximum of 100 W. Echocardiographic measurements were performed at rest and at peak exercise. The study was designed to detect an effective regurgitant orifice (ERO) change of at least 10 mm² during exercise. Results: Twenty‐six patients (21 male, age 56 ± 12 years (mean ± SD)) were included. Patients had an ERO of 35 ± 23 mm² (mean ± SD) and regurgitation volume of 48 ± 38 mL (mean ± SD). In these patients, ERO remained unchanged (an increase of 2 ± 15 mm² during exercise, P = 0.6). The regurgitation volume (RVol) decreased with 11 ± 16 mL (mean ± SD), P = 0.003. When calculated for 1 minute, RVol increased during exercise (P = 0.01), but in relation to the total cardiac output it decreased significantly (P = 0.02). Conclusion: Exercise does not increase the severity of MR due to MVP, in contrast to MR secondary to IHD. Different disease mechanisms behind these two types of MR could explain this difference. (Echocardiography 2010;27:1031‐1037)     

Determinants of pulmonary venous flow reversal in mitral regurgitation and its usefulness in determining the severity of regurgitation

Pulmonary venous flow (PVF) reversal is observed in mitral regurgitation (MR) and can be detected by Doppler echocardiography. However, the determinants of PVF alterations in MR have not been analyzed with simultaneous quantitative methods, and the diagnostic accuracy of flow reversal is uncertain. Prospectively, in 128 patients with isolated MR of various degrees (regurgitant fraction 4% to 81%), Doppler echocardiography was used to measure PVF velocity simultaneously to quantify MR by 2 methods and to perform a comprehensive hemodynamic assessment. Systolic PVF velocity was 4 +/- 56 cm/s (systolic flow reversal in 39 patients) and showed the strongest correlations with mitral effective regurgitant orifice (r = -0.56, p <0.0001). In multivariate analysis, larger effective regurgitant orifice (p <0.0001), eccentric jets (p = 0.0023), longer jets (p = 0.0033), and lower mitral regurgitant velocity (p = 0.0015) were independent determinants of decreased systolic PVF velocity. In organic MR, increased filling pressures were associated with systolic PVF reversal. Blunted systolic flow was associated with shorter mitral deceleration time (p <0.0001) and enlarged left atrium (p = 0.0007). For the diagnosis of severe MR (regurgitant orifice > or = 35 mm2, regurgitant fraction > or = 50%), systolic flow reversal sensitivity was 61% and 60%, and specificity was 92% and 85%, respectively. Among 29 patients in whom surgery demonstrated severe mitral lesions, 12 (41%) had no systolic flow reversal preoperatively. In patients with MR, the determinants of systolic PVF are complex and, in addition to the degree of MR, include the hemodynamic consequences of MR, jet characteristics, left ventricular filling, and left atrial volume alterations. Consequently, systolic PVF reversal is a useful sign of severe MR but of relatively low sensitivity, emphasizing the importance of quantifying MR.